Trouble with Tare weight calculation

I think I am having trouble with the tare weight calculation. THe net result is that I undercharge the customer. Here are the details.

The product weighs 4.75 lbs.
When I have the parameter "Package Tare Small to Medium add percentage: weight" set to 30:.5 the cart calculates $23.55 for the USPS shipping cost. I am using the USPS api to get the shipping cost.

When I set it to 50:.5 the cart calculates $24.99
When I set it to 100:.5 the cart calculates $27.90
I am shipping from 55398 to 22066

It seems like the percentage change does not have a very significant effect on the shipping cost. I think that going from 30% to 100% should have a drastic effect on the cost, but the real effect is fairly minor.
Thank you for your help.

Let me make a quick correction. There is actually 3 units in the example above for a total of 14.25 Lbs.

It looks like I have a similar problem. My tare rate for small packages is set to 25:.5, but it appears that this never takes affect on the calculated shipping. The weight that is displayed in the shipping estimator is net weight only and the amount of shipping reflects that weight.

Can anyone shed light on this?

thanks

I have product whose weight is .2 (kg/lb doesn't matter)

Package Tare Small to Medium - added percentage:weight 25:.5

The weight that's calculated on the shopping cart page shows .75
By my calculations is should show .55

Any have any ideas

Hi Shocker,

I have product whose weight is .2 (kg/lb doesn't matter)
Package Tare Small to Medium - added percentage:weight 25:.5

The weight that's calculated on the shopping cart page shows .75

That is correct.

By my calculations is should show .55

Check again:

25% of 0.2 = 0.05

0.05 + 0.5 = 0.55

0.55 + 0.2 = 0.75

Methinks you probably forgot to add the weight of the item ;-)

Cheers
Rod

Oh WoW!

and to think I teach 7th grade math. What a foobar!

Thanx Rod